(2013·湖南高考)He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
A．wouldn't B．shouldn't
C．couldn't D．mustn't
(2013·江西高考)When I was a child, I ________ watch TV whenever I wanted to.
A．should B．could
C．must D．need
—Which one of these two dictionaries do you advise me to buy, Oxford or Longman?
—Well, take Oxford. I think it is the ________ of the two.
A．best B．better
C．good D．well
Nothing that you say can change his mind, ________？
A．do you B．don't you
C．can it D．can't it
The smoggy weather has made us realize ________ terrible problems we are faced with.
A．how B．what
C．that D．which
—How unhappy your roommate looks!
—Yes, but he's not willing to tell me what it is ________ is troubling him.
A．what B．which
C．as D．that
